A clinical response was defined as reduction of at least 100 from the baseline score on the Crohn's Disease Activity Index at week 6.

Patients with a clinical response were stratified according to their baseline C-reactive protein level.

The team then randomly assigned the patients to receive 400 mg of certolizumab pegol or placebo every 4 weeks through week 24, with follow-up through week 26.

Among patients with a response to induction therapy at week 6, the response was maintained through week 26 in 62% with a baseline C-reactive protein level of at least 10 mg per liter who were receiving certolizumab pegol.

The response to induction therapy was maintained in 63% in the intention-to-treat population who were receiving certolizumab pegol vs 36% receiving placebo.

Remission was defined by a Crohn's Disease Activity Index score of 150.

At week 26, the team observed that 48% of patients in the certolizumab group, and 29% of those in the placebo group were in remission.

The efficacy of certolizumab pegol was also shown in patients taking, and those not taking glucocorticoids or immunosuppressant.

The researchers noted the efficacy of certolizumab pegol in patients who had, and those who had not previously taken infliximab.

The team found infectious serious adverse events occurred in 3% of patients receiving certolizumab pegol, and in less than 1% of patients receiving placebo.

Antinuclear antibodies developed in 8% of the patients in the certolizumab group.

The research team found that antibodies against certolizumab pegol developed in 9% of all patients who entered the induction phase.

Dr Schreiber' team concluded, "Patients with moderate-to-severe Crohn's disease who had a response to induction therapy with 400 mg of certolizumab pegol were more likely to have a maintained response and a remission at 26 weeks with continued certolizumab pegol treatment than with a switch to placebo."